Survivors of a university massacre in Kenya where Islamist gunmen killed 148 people have recounted scenes of terror at a trial of five men linked to the slaughter.

The deadly attack at Garissa University in northeastern Kenya on April 2, 2015, was claimed by Somalia's Al-Qaida-linked Shebab insurgents. It was the East African nation's deadliest attack since the 1998 bombing of the U.S. embassy in Nairobi.

Gunmen killed two Kenyan policemen and wounded two others on Sunday, the Red Cross said, the latest in a string of killings in the troubled far northeast of the country.

"Two police officers killed and two others injured in an ambush along Lafey-Elwak road, Mandera county," the Kenya Red Cross said in a statement.

Kenyan police warned Thursday of the risk of attacks by Islamist Shebab insurgents claiming they had split into rival factions, with some shifting allegiance from Al-Qaida to Islamic State.

"They have split, and as a result of the split, particularly those ones along ideological lines or religious lines are very keen to promote that competition by proving a point," police chief Joseph Boinnet told reporters Thursday, as Kenyans prepare to celebrate Christmas in the east African nation.

A Kenyan man has been charged with receiving Iranian training in Iraq to carry out attacks in the east African country.

Kenyan police say Yassin Sambai Juma, 25, was trained by Iran's elite Quds Force -- claims denied by Tehran, and was charged in court on Monday.

Kenyan police have arrested two men who were allegedly recruited by an Iranian group accused of plotting attacks in the east African nation, the police chief said Saturday.

Police chief Joseph Boinett said they believed the two Kenyan men had traveled to Iran several times, identifying them as Abubakar Sadiq Louw, 69, and Yassin Sambai Juma. Kenyan media gave his age as 25.

An official Kenyan human rights watchdog on Tuesday accused security forces of a wave of rights abuses including torture and murder amid the east African nation's own "war on terror."

A report by the Kenya National Commission on Human Rights (KNCHR), a state-funded body, listed 25 extra-judicial killings, 81 forced disappearances and the use of torture including waterboarding, electric shocks, genital mutilation, mock executions and exposure to stinging by ants in the wild.

Kenyan forces on Friday launched a massive security operation in a forest in the country's coastal northeast which officials say is being used as a hideout by Somalia's al-Qaida-affiliated Shebab rebels.

Interior Minister Joseph Nkaissery launched the operation a week after police warned the area's residents to hand over any weapons and leave ahead of an "imminent security operation."

Dozens have been killed in Somalia after Shebab gunmen ambushed an army convoy, officials and local elders said Thursday, the latest battles with the al-Qaida-linked insurgents.

Shebab fighters launched attacks on the army convoy near the village of Tulo-Barwao in the southwestern Gedo district of Somalia on Wednesday, a region bordering Ethiopia and Kenya, sparking intense gun battles.

The International Criminal Court on Wednesday told judges to review their decision not to refer Kenya to the court's oversight body for failing to cooperate in the case against President Uhuru Kenyatta.

Prosecutors in late 2013 asked the Hague-based ICC to rule that Nairobi failed to act on a prosecution request to hand over Kenyatta's financial records, phone statements and other documents they said could prove their crimes against humanity case against the president.

At least 310 Kenyans have been killed and over 215,000 forced from their homes this year in ethnic violence in northern Kenya, the U.N. said Wednesday.

While violence between rival groups is common in Kenya's northern Rift Valley regions, the number killed and forced to flee in the first six months of this year is already the same as the total for all of 2014.